7 accepted papers
Stereo and multi-channel audio coding for mobile communication applications is challenging due to bitrate, latency and computational complexity constraints. To address these constraints, a novel MDCT-based stereo coding scheme is introduced. A key feature of this scheme is the broadband inter-channe…
The objective PSNR metric is known to correlate quite poorly with subjective assessments of video coding quality. Thus, a number of alternative VQA measures such as (MS-)SSIM and VMAF have been proposed. These, however, are often algorithmically complex and difficult to use for visually motivated en…
Contemporary perceptual audio coders, all of which apply the modified discrete cosine transform (MDCT), with an overlap ratio of 50%, for frequency-domain quantization, provide good coding quality even at low bit-rates. However, relatively long frames are required for acceptable low-rate performance…
Unified speech and audio codecs often use a frequency domain coding technique of the transform coded excitation (TCX) type. It is based on modeling the speech source with a linear predictor, spectral weighting by a perceptual model and entropy coding of the frequency components. While previous appro…
Speech coders operating in time domain can be extended with a frequency domain mode to improve encoding of music, even though this is challenging at low delay. In such a scenario, the short analysis window limits the benefit of the transform coder, while a delayless switch between the two coders con…
Several state-of-the-art switched audio codecs employ the closed-loop mode decision to select the best coding mode at every frame. The closed-loop mode selection is known to have good performance but also high complexity. The new approach we propose in this paper is a low-complexity version of the c…
In low-bitrate audio coding, modern coders often rely on efficient parametric techniques to enhance the performance of the waveform preserving transform coder core. While the latter features well-known perceptually adapted quantization of spectral coefficients, parametric techniques reconstruct the…